Improvement in furnaces



UNITED STATES PATENT OFFICE.,

IMPROVEMENT lN FU RNACES.

Specification forming part of Letters Patent No. 18,432, dated Ovtoher20. 1857.

llo all whom it may concern:

Be it known that we, JOHN CASE and Isaac SOULES, both of Amsterdam,inthe county of Montgomery and State of New York, have invented a new anduseful Improvement in Furnaces, specially adapted to the generation ofsteam for motive power, but applicable to furnaces for other purposes,of which the follow ing is a full, clear, and exact description,reference beine had to the accompanying drawings, in Which- Figure lrepresents a side elevation of a single-fine steamhoiler embracing ouriur provement. Fig. 2 represents a horizontal longitudinal sectionthrough the same. liig. I; represents a transverse section through thesmoke-box at the line a' .1f of Fig. 1, and Fig. 4 represents atransverse section through the furnace at the line o 0 of Fig. l.

The principal objects of our invention are to economize fuel in the`generation of steam for motive power by burning,` most of thecombustible matter that usually escapes nncousumed by the chimney, todiminish the quantity of smoke, and thereby lessen its capacity forcarrying olf heat when it escapes, and incidentally to extinguish thesparks and prevent their escape. These objects are accomplisl'ied byburning't the fuel in a close furnace through which a regular current offresh air mingled with the gaseous products of combustion is constantlyflowing. This current is established by connectinpl the t'nrnace andsmoke-box by two iiues or series of iiues, through one ot' which thegases can pass from the furnace to the smoke-box and through the otherreturn from the smokebox to the furnace, a fan or other suitable pumphcingarranged in the circuit to maintain the current at a propervelocity. As thc gases enter the smoke-box they are mingled with coolair, thence passing" into the tan-case are forced bv the fan through thereturn-line back into the furnace, where they are again iniiamed, andpass through the i'lues ot' the boiler into the smoke-box to be againmingled with air. vliy this operation the gaseous products arealternately mixe'd with fresh air, reheated, and inflamed until they arethoroughly oxidated, most of the heat which they evolve during theprocess of oxidation being transferred to the Water in the boiler,

after which they are so reduced in bulk and increased in weight as tosettle by their own gravity to the bottom of the smoke-box, throughwhich they escape by a small opening provided for the purpose. Thesparks also settle to the bottom of this receptacle and are extinguishedby the burned and uninllammable gas in which they are immersed.

In the accompanying drawings a boiler to which our improvement isapplied is shown. The boiler consists of a cylindrical shell A and flueB, connected at one end with a tirechamber C and at the other with asmokebox I). '.lhe iire-chamber (l is provided with suitable tight doorsE E' both above and bclow the grate-bars. 'lhe upper one E is used tosupply the furnace with t'uel from time to time, as required, and thelower one E' to give access to the ash-pit. A valvular feeding-hoppermaybe used instead of the upper door to supply the furnace with fuel.The tine I; forms a communication between the fire-chamber andsmoke-box, through which the gaseous products of combustion pass withthe sparks from the furnace to the smokebox. An orifice J, fitted with avalve by which it can he opened and closed at pleasure, ente rs theupper part ot' the smoke-box to supply the fresh air necessary for thecombustion of the fuel.

A fan l?, constructed like the ordinary fanblower, is placed ou one sideof the smoke box with sufficient space around the fan-case for the gasesto enter it freely. A pipe G on the outside of the boiler (one end ofwhich enters the furnace beneath the grate-bars and the other passesthrough the smoke-box and terminates in the fan'case) fol-insacommunication between the smoke-box and the furnace through thefan-case. This pipe after leaving' the fan-case may he forked, onebranch entering' the tire-box below the gratehars and the otherentering,` the lire-box just above the fuel on the grate, by which meansthc unconsumed gases mixed with air would enter the tire-box both aboveand below the grate-bars.

L'nder the arrangement ot' the [an here adopted its axle extends throughthe sides of the smoke-box and is supported in suitable bearings Il,formed in the sides of the box. On one of the projecting ends of theaxle is a pulley I, by which motion is given to the fan in the usualmanner. 0n the top of the smoke-box there is a chimney, which is fittedwith a valve K, to he opened tocreate a draft while the tire is beingkindled and also duringl the time fuel is being fed into the furnace,that the gases may not be blown out at the furnace-door. ln order toavoid opening the valve in the chimney during the feeding of thefurnace, a valve may be placed in the return-pipe leading from the fan,which the opening of the furnace-door will close; or if a valvularfeeding-hopper is used the opening of this valve l( while feeding willbe unnecessary. As soon as the tire has been Well kindled thefurnace-doors and chimney-valve are closed, the valve L of theair-orilice J is opened, and thc fan put in motion. Air for the supportof combustion is drawn through the orifice J into the smoke-boxandmingled u ilh the gases in the upper part of the box, :ind thus mingledthe two are forcedby the fan into the furnace beneath the grate-bars,and as they pass through the fuel lying on the grate-bars a portion ot'the oxygen of the air mixed with the return gases is taken up by thefuel` and thus its combustion is maintained, while the remainder of theoxygen of the air combines with the gases as they are heated in passingthrough thc furnace, t0 complete their combustion. 0n the passage ofthese gases through the titles a portion of their heat is taken up andimparted to the water by which they are surrounded. Those portions ofthc gases which have been saturated with oxygen an'd cooled by passingthrough the lilies become heavier than the less oxidated and inflammableportions, and as these heavy saturated gases come in coutact with thecool fresh air of the smoke-box as they issue from the direct line theirtemperature is still further reduced and their density increased, andthey settle to the bottom ofthe smoke-box and pass out through thewaste-pipe M. 'lhelighter and partiallyoxidated gases mingled with thecurrent of fresh air are drawn into the fan-ease and forced back throughthe furnace, as already described, and the process of alternate mixingwith fresh air and burning is repeated until thc combustion of the gasesis completed. 'lhc motion of the fan while producing this circulationcreates a partial vacuum in the smoke-box, which draws the gases fromthe tire-box and causes thc fresh air to enter through the orifice J.Owing to the en trance of the air at the upper part of the smoke-box itflows among and becomes inti mately mixed with the gases before theyenter the fau, and the agitation produced by the rotation of the fanblends them still mol'e intimately. Then these gases mingled with freshair pass through the interstices bctween the pieces of solid fucl on thegratebars, a portion of the oxygen derived from the fresh air goes tothe support of the com bustion of the solid fuel, causing it to burnfreely, while the remainder is gradually combined with the gases, asalready mentioned. This intimate mixture of the fresh air with the gasesbefore they enter the ash-pit is essential to the uniform combustionboth of the solid fuel lying on the grate and of the gases, for if thegases were introduced beneath the grate-bars through one opening While acurrent of fresh air entered through another the air would pass throughthe gratos almost uumingled with gases and produce an intense heatandrapid combustion of the fuel lying on the grate in thc immediate pathof the air toward the flue, while the fuel on the other portions of thegrate would he deadened if its combustion were not quenched by the gaseswhich would pass back again to the smoke-box, little, if any, moreoxidated than when they left it, by which means neither the solid northe gaseous fuel would be prop erly burned for want of a thoroughmingling of the air and gases before entering the ashpit. Much of thoseportions of the gases which are so saturated with oxygen as to beincombustible and yet not sufficiently cool to settle freely as theyissue from the direct liuc are cooled by coming in contact with thefresh air and then settle tothe bottom of the smoke-chamber and escape.

In applying our improvement to existing furnaces it will be necessaryfrequently lo vary the position of the smoke-box, fan, and return-finesto adapt them to particular circumstances. The fan must, however, in allcases be located at some point between the end of the direct lines andthe lire-box.

\Vhat we claim as our invention, and desire to secure by Letters Patent,is-

'lhe combination and arrangement of the lire and smoke boxes, direct andreturn [i ues, the valved atmospheric-air orifice and aperture for theescape of the spent gases, and the fan for maintaining the circulationof the air and gases, arranged substantially as before declared.

ln testimony whereof we have hereunto subscribed our names.

JOHN C X'slll. ISAAC SOULES.

J Anus FRENUH.

